To determine if apparent diffusion coefficients (ADC) can discriminate between posterior fossa brain tumours on a multicentre basis. A total of 124 paediatric patients with posterior fossa tumours (including 55 Medulloblastomas, 36 Pilocytic Astrocytomas and 26 Ependymomas) were scanned using diffusion weighted imaging across 12 different hospitals using a total of 18 different scanners. Apparent diffusion coefficient maps were produced and histogram data was extracted from tumour regions of interest. Total histograms and histogram metrics (mean, variance, skew, kurtosis and 10th, 20th and 50th quantiles) were used as data input for classifiers with accuracy determined by tenfold cross validation. Mean ADC values from the tumour regions of interest differed between tumour types, (ANOVA P < 0.001). A cut off value for mean ADC between Ependymomas and Medulloblastomas was found to be of 0.984 × 10−3 mm2 s−1 with sensitivity 80.8% and specificity 80.0%. Overall classification for the ADC histogram metrics were 85% using Naïve Bayes and 84% for Random Forest classifiers. The most commonly occurring posterior fossa paediatric brain tumours can be classified using Apparent Diffusion Coefficient histogram values to a high accuracy on a multicentre basis.

Background 1H-magnetic resonance spectroscopy (MRS) facilitates noninvasive diagnosis of pediatric brain tumors by providing metabolite profiles. Prospective studies of diagnostic accuracy and comparisons with conventional MRI are lacking. We aimed to evaluate diagnostic accuracy of MRS for childhood brain tumors and determine added clinical value compared with conventional MRI. Methods Children presenting to a tertiary pediatric center with brain lesions from December 2015 through 2017 were included. MRI and single-voxel MRS were acquired on 52 tumors and sequentially interpreted by 3 radiologists, blinded to histopathology. Proportions of correct diagnoses and interrater agreement at each stage were compared. Cases were reviewed to determine added value of qualitative radiological review of MRS through increased certainty of correct diagnosis, reduced number of differentials, or diagnosis following spectroscopist evaluation. Final diagnosis was agreed by the tumor board at study end. Results Radiologists’ principal MRI diagnosis was correct in 69%, increasing to 77% with MRS. MRI + MRS resulted in significantly more additional correct diagnoses than MRI alone (P = .035). There was a significant increase in interrater agreement when correct with MRS (P = .046). Added value following radiologist interpretation of MRS occurred in 73% of cases, increasing to 83% with additional spectroscopist review. First histopathological diagnosis was available a median of 9.5 days following imaging, with 25% of all patients managed without conclusive histopathology. Conclusions MRS can improve the accuracy of noninvasive diagnosis of pediatric brain tumors and add value in the diagnostic pathway. Incorporation into practice has the potential to facilitate early diagnosis, guide treatment planning, and improve patient care.

have contributed equally to this study and should be considered as co-first authors. IntroDuCtIon Brain tumours are the biggest cause of death from cancer in children. 1 Radiological assessment is one of the key tools used in the management of this patient cohort. The primary imaging modality now employed is MRI which provides a clear picture of the internal soft tissue structure of the brain. Advanced MRI techniques are able to probe metabolism, blood flow and cellularity via a range of methods. 2 Perfusion MRI, which provides estimates of cerebral blood flow (CBF) and relative cerebral blood volume (rCBV), has become increasingly pertinent as the use of antivascular and anti-angiogenic

Introduction Management of posttraumatic bile leak has evolved over time in our unit, from endoscopic retrograde cholangiopancreatography (ERCP) stenting to intraperitoneal drainage (IPD) alone as first-line treatment for intraperitoneal bile leak. Materials and Methods Retrospective review of liver trauma patients from 2002 to 2017. Demographics, time and mode of diagnosis of bile leak, management, and outcome were analyzed of the box plot. Results In 118 patients, there were 28 traumatic bile leaks. Eighteen were free intraperitoneal and 10 were localized bilomas. The median time of diagnosis was 6 days following injury. The modes of diagnosis were preemptive hepatobiliary scintigraphy (18), computed tomography (CT) or ultrasound (7), and laparotomy (3). Free intraperitoneal biliary leak management included 11 IPD alone, 3 IPD plus ERCP, 2 IPD plus transcystic biliary stent (TBS), 1 operative cholangiogram, and 1 no intervention. Median time of IPD duration was 7 days (4–95) in IPD alone versus 14 days (6–40) in IPD + ERCP/TBS (p = 0.3). Median inpatient length of stay was 13 days (8–44) in IPD alone versus 12 days (8–22) in IPD + ERCP/TBS (p = 0.4). Conclusion Placement of IPD alone, as first-line treatment, is safe and effective in the management of intraperitoneal bile leaks, avoiding the costs and potential complications of ERCP.

ObjectiveThis study aimed to explore the anatomical features of aortic arch anomalies associated with vascular rings, hoping to identify those which may increase the risk of symptomatic presentation and surgical intervention.MethodsThis was a retrospective observational study at a single cardiac unit. Individuals diagnosed with an aortic arch anomaly, either isolated or non-isolated, between June 2014 and September 2018 were included. The morphology of the aortic arch was established via analysis of postnatal echocardiography, CT or MRI scans. CT and magnetic resonance studies were evaluated for the presence of a Kommerell diverticulum in those with aberrant vessels. Case notes were reviewed for relevant clinical data.ResultsOf those with aberrant subclavian arteries, 24/79 (30.4%) were shown to have a Kommerell diverticulum. Additional forms of congenital heart disease were present in 133/227 (58.6%) individuals. Surgical division of the vascular ring was performed in 30/227 (13.2%), most commonly in the setting of a double aortic arch (70.8%). In those with aberrant subclavian arteries, no children without a Kommerell diverticulum were referred for surgery. In those with a Kommerell diverticulum confirmed on imaging, 11/24 underwent surgery.ConclusionIndividuals with a double aortic arch, or an aberrant subclavian artery arising from a Kommerell diverticulum, have the highest requirement for surgical intervention, especially in isolated anomalies. These individuals should remain under monitoring. The subjective nature of symptoms remains problematic. Longitudinal research is required further to understand the natural history of vascular rings and how it links to morphology.